Lync Server archiving agent is unable to send the message to Message Queuing queue. Queue: %1 Acknowledgement class: %2. ...

Lync Server archiving agent is unable to send the message to Message Queuing queue.


Queue: %1 
Acknowledgement class: %2. 
%3
Cause: This can happen if the archiving agent receives a negative acknowledgement from the service, and one or more messages have been dropped.
Resolution:
Verify Lync Server archiving agent permissions, that the message queue still exists, that the queue is not full, and that there is enough free disk space.